Cannot load mysqli extension - WAMP Server

I started work this morning and when I went to access phpMyAdmin which is installed as part of the WAMP package on a Windows 7 box I got the error "Cannot load mysqli extension". I wasn't sure at first what could have caused it but I figured the obvious thing to do was to replace the extensions so I downloaded the PHP binaries and replaced the mysql and mysqli extensions in the WAMP installation but that didn't help. After a few minutes of thinking I remembered I had installed Zend Server the Friday before for some testing. The error is caused because Zend installs another php.ini file. I simply removed Zend Server altogether because it was no longer needed but you could also have renamed the php.ini file or as a better option removed the php.ini file and then make sure your global $PATH variable is updated so that all of your servers can share the same php installation.